Method for Making an Epoxide Starting with a Polyhydroxylated Aliphatic Hydrocarbon and a Chlorinating Agent

ABSTRACT

Process for preparing an epoxide, wherein a reaction medium resulting from the reaction of a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium, is subjected to a subsequent chemical reaction without intermediate treatment.

The present patent application claims the benefit of patent applicationFR 05.05120 and of patent application EP 05104321.4, both filed on 20May 2005, and of provisional U.S. patent applications 60/734,659,60/734,627, 60/734,657, 60/734,658, 60/734,635, 60/734,634, 60/734,637and 60/734,636, all filed on 8 Nov. 2005, the content of which isincorporated here by reference.

The present invention relates to a process for preparing an epoxide.Epoxides are important raw materials for the production of othercompounds.

Ethylene oxide is used, for example, for the production of ethyleneglycol, of di- and polyethylene glycols, of mono-, di- andtriethanolamines, etc. (see K. Weissermel and H.-J. Arpe in IndustrialOrganic Chemistry, Third, Completely Revised Edition, VCH, 1997, page149). Propylene oxide is an important intermediate in the preparation ofpropylene 1,2-glycol, of dipropylene glycol, of ethers of propyleneglycol, of isopropylamines, etc. (see K. Weissermel and H.-J. Arpe inIndustrial Organic Chemistry, Third, Completely Revised Edition, VCH,1997, page 275). Epichlorohydrin is an important raw material for theproduction of glycerol, of epoxy resins, of synthetic elastomers, ofglycidyl ethers, of polyamide resins, etc. (see Ullmann's Encyclopediaof Industrial Chemistry, Fifth Edition, Vol. A9, p. 539).

In the industrial production of propylene oxide the most commonly usedtechnology comprises the following steps: hypochlorination of propyleneto monochloropropanol and dehydrochlorination of the monochloropropanolto propylene oxide by means of an aqueous alkaline solution.

In the industrial production of epichlorohydrin the most commonly usedtechnology comprises the following steps: high-temperature free-radicalsubstitutive chlorination of propylene to allyl chloride,hypochlorination of the allyl chloride thus synthesized todichloropropanol, and dehydrochlorination of the dichloropropanol toepichlorohydrin by means of an aqueous alkaline solution. Anothertechnology, used on a smaller scale, comprises the following steps:catalytic acetoxylation of propylene to allyl acetate, hydrolysis of theallyl acetate to allyl alcohol, catalytic chlorination of the allylalcohol to dichloropropanol, and alkaline dehydrochlorination of thedichloropropanol to epichlorohydrin. Other technologies, which have notyet gained industrial application, may be considered, including thedirect catalytic oxidation of allyl chloride to epichlorohydrin usinghydrogen peroxide, or the chlorination of glycerol to dichloropropanol,followed by alkaline dehydrochlorination of the dichloropropanol thusformed to epichlorohydrin.

Application WO 2005/054167 of SOLVAY SA describes a process forpreparing dichloropropanol by reacting glycerol with hydrogen chloridein the presence of an organic acid as catalyst. In that process thedichloropropanol is separated from the other products of the reaction,the hydrogen chloride and the organic acid and the dichloropropanol issubjected to a dehydrochlorination reaction so as to give reactionproducts containing epichlorohydrin. The dehydrochlorination may becarried out in the presence of a basic agent and, in particular, of anaqueous solution of a basic agent. The separation of the organic acid isinconvenient if it forms an azeotrope with water or if its relativevolatility is significant in the ternary water/dichloropropanol/hydrogenchloride mixture, and in that case the dichloropropanol is alsocontaminated with the esters that it forms with the organic acid.

The objective of the present invention is to provide a process forpreparing an epoxide that does not exhibit these drawbacks.

The invention accordingly provides a process for preparing an epoxide,wherein a reaction medium resulting from the reaction of apolyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylatedaliphatic hydrocarbon or a mixture thereof with a chlorinating agent,the reaction medium containing at least 10 g of chlorohydrin per kg ofreaction medium, is subjected to a subsequent chemical reaction withoutintermediate treatment.

The subsequent chemical reaction is preferably a dehydrochlorinationreaction.

The dehydrochlorination reaction is preferably carried out by adding abasic compound to the reaction medium.

The invention more specifically provides a process for preparing anepoxide, comprising the following steps:

-   -   (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a        polyhydroxylated aliphatic hydrocarbon or a mixture thereof is        reacted with a chlorinating agent and an organic acid so as to        form the chlorohydrin and chlorohydrin esters in a reaction        medium containing the polyhydroxylated aliphatic hydrocarbon,        the ester of a polyhydroxylated aliphatic hydrocarbon, water,        the chlorinating agent and the organic acid, the reaction medium        containing at least 10 g of chlorohydrin per kg of reaction        medium,    -   (b) at least a fraction of the reaction medium obtained in step        (a), this fraction having the same composition as the reaction        medium obtained in step (a), is subjected to one or more        treatments in steps subsequent to step (a),    -   (c) a basic compound is added to at least one of the steps        subsequent to step (a), in order to react with the chlorohydrin,        the chlorohydrin esters, the chlorinating agent and the organic        acid, so as to form the epoxide and salts.

It has now been found that separating the organic acid and itsderivatives is not indispensable, since by subjecting a mixturecontaining the chlorohydrin, the chlorinating agent and an organic acidto a reaction with a basic compound it is possible to produce an epoxidewith an excellent yield. Surprisingly, the formation of salts resultingfrom the neutralization of the chlorinating agent and of the organicacid by the basic compound, and the hydrolysis of the esters formedbetween the chlorohydrin and the organic acid, do not disrupt theprocess for preparing the epoxide, even when substantial quantities oforganic acid are present in the step of reaction (c) with the basiccompound. A significant advantage of the process is that it is notnecessary to separate the chlorinating agent and the organic acid thatare used in the step of preparing the chlorohydrin.

The term “epoxide” is used here to describe a compound containing atleast one oxygen bridged on a carbon-carbon bond. In general the carbonatoms of the carbon-carbon bond are adjacent and the compound maycontain atoms other than carbon and oxygen atoms, such as hydrogen atomsand halogens. The preferred epoxides are ethylene oxide, propyleneoxide, glycidol and epichlorohydrin, and mixtures of at least twothereof.

The term “olefin” is used here to describe a compound containing atleast one carbon-carbon double bond. In general the compound may containatoms other than carbon atoms, such as hydrogen atoms and halogens. Thepreferred olefins are ethylene, propylene, allyl chloride and mixturesof at least two thereof.

The term “polyhydroxylated aliphatic hydrocarbon” refers to ahydrocarbon which contains at least two hydroxyl groups attached to twodifferent saturated carbon atoms. The polyhydroxylated aliphatichydrocarbon may contain, but is not limited to, from 2 to 60 carbonatoms.

Each of the carbons of a polyhydroxylated aliphatic hydrocarbon carryingthe hydroxyl (OH) functional group may not possess more than one OHgroup and must be of sp3 hybridization. The carbon atom carrying the OHgroup may be primary, secondary or tertiary. The polyhydroxylatedaliphatic hydrocarbon used in the present invention must contain atleast two sp3-hybridized carbon atoms carrying an OH group. Thepolyhydroxylated aliphatic hydrocarbon includes any hydrocarboncontaining a vicinal diol (1,2-diol) or a vicinal triol (1,2,3-triol),including higher orders of these repeating units, which are vicinal orcontiguous. The definition of the polyhydroxylated aliphatic hydrocarbonalso includes, for example, one or more 1,3-, 1,4-, 1,5- and 1,6-diolfunctional groups. The polyhydroxylated aliphatic hydrocarbon may alsobe a polymer such as polyvinyl alcohol. Geminal diols, for example, areexcluded from this class of polyhydroxylated aliphatic hydrocarbons.

The polyhydroxylated aliphatic hydrocarbons may contain aromaticmoieties or heteroatoms including, for example, heteroatoms of halogen,sulphur, phosphorus, nitrogen, oxygen, silicon and boron type, andmixtures thereof.

Polyhydroxylated aliphatic hydrocarbons which can be used in the presentinvention include, for example, 1,2-ethanediol (ethylene glycol),1,2-propanediol (propylene glycol), 1,3-propanediol,1-chloro-2,3-propanediol (chloropropanediol), 2-chloro-1,3-propanediol(chloropropanediol), 1,4-butanediol, 1,5-pentanediol, cyclohexanediols,1,2-butanediol, 1,2-cyclohexanedimethanol, 1,2,3-propanetriol (alsoknown as glycerol or glycerin), and mixtures thereof. With preferencethe polyhydroxylated aliphatic hydrocarbon used in the present inventionincludes, for example, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol,chloropropanediol and 1,2,3-propanetriol, and mixtures of at least twothereof. More preferably the polyhydroxylated aliphatic hydrocarbon usedin the present invention includes, for example, 1,2-ethanediol,1,2-propanediol, chloropropanediol and 1,2,3-propanetriol and mixturesof at least two thereof. 1,2,3-Propanetriol, or glycerol, is the mostpreferred.

The esters of the polyhydroxylated aliphatic hydrocarbon may be presentin the polyhydroxylated aliphatic hydrocarbon and/or may be produced inthe process of preparing the chlorohydrin and/or may be prepared priorto the process of preparing the chlorohydrin. Examples of esters ofpolyhydroxylated aliphatic hydrocarbon include ethylene glycolmonoacetate, propanediol monoacetates, glycerol monoacetates, glycerolmonostearates, glycerol diacetates and mixtures thereof.

The term “chlorohydrin” is used here to describe a compound containingat least one hydroxyl group and at least one chlorine atom which areattached to different saturated carbon atoms. A chlorohydrin whichcontains at least two hydroxyl groups is also a polyhydroxylatedaliphatic hydrocarbon. Hence the starting material and the product ofthe reaction may each be chlorohydrins. In that case the “product”chlorohydrin is more chlorinated than the starting chlorohydrin; inother words, it has more chlorine atoms and fewer hydroxyl groups thanthe starting chlorohydrin. Preferred chlorohydrins are chloroethanol,chloropropanol, chloropropanediol, dichloropropanol and mixtures of atleast two thereof. Dichloropropanol is particularly preferred.Chlorohydrins which are more particularly preferred are 2-chloroethanol,1-chloropropan-2-ol, 2-chloro-propan-1-ol, 1-chloropropane-2,3-diol,2-chloropropane-1,3-diol, 1,3-dichloro-propan-2-ol,2,3-dichloropropan-1-ol and mixtures of at least two thereof.

The polyhydroxylated aliphatic hydrocarbon, the ester ofpolyhydroxylated aliphatic hydrocarbon, and mixtures thereof, and thechlorohydrin in the process according to the invention may be obtainedstarting from fossil raw materials or starting from renewable rawmaterials, preferably starting from renewable raw materials.

By fossil raw materials are meant materials obtained from the treatmentof petrochemical natural resources, for example petroleum, natural gasand coal. Among these materials the organic compounds containing 2 and 3carbon atoms are preferred. When the chlorohydrin is dichloropropanol orchloropropanediol, allyl chloride, allyl alcohol and “synthetic”glycerol are particularly preferred. By “synthetic” glycerol is meant aglycerol obtained generally starting from petrochemical resources. Whenthe chlorohydrin is chloroethanol, ethylene and “synthetic” ethyleneglycol are particularly preferred. By “synthetic” ethylene glycol ismeant an ethylene glycol obtained generally starting from petrochemicalresources. When the chlorohydrin is monochloropropanol, propylene and“synthetic” propylene glycol are particularly preferred. By “synthetic”propylene glycol is meant a propylene glycol obtained generally startingfrom petrochemical resources.

By renewable raw materials are meant materials obtained from thetreatment of renewable natural resources. Among these materials“natural” ethylene glycol, “natural” propylene glycol and “natural”glycerol are preferred. “Natural” ethylene glycol, propylene glycol andglycerol are obtained, for example, by conversion of sugars viathermochemical processes, it being possible for these sugars to beobtained starting from biomass, as described in “Industrial Bioproducts:Today and Tomorrow”, Energetics, Incorporated for the U.S. Department ofEnergy, Office of Energy Efficiency and Renewable Energy, Office of theBiomass Program, July 2003, pages 49, 52 to 56. One of these processesis, for example, the catalytic hydrogenolysis of sorbitol obtained bythermochemical conversion of glucose. Another process is, for example,the catalytic hydrogenolysis of xylitol obtained by hydrogenatingxylose. The xylose may be obtained, for example, by hydrolyzing thehemicellulose present in maize fibres. By “natural glycerol” or by“glycerol obtained starting from renewable raw materials” is meant, inparticular, glycerol obtained during the production of biodiesel or elseglycerol obtained in the course of conversions of animal or vegetableoils or fats in general, such as saponification, transesterification orhydrolysis reactions.

Among the oils which can be used for preparing the natural glycerolmention may be made of all customary oils, such as palm oil, palm kerneloil, copra oil, babassu oil, former or new (low erucic acid) colza,sunflower oil, maize oil, castor oil and cotton oil, peanut oil,soyabean oil, linseed oil and crambe oil, and all oils obtained, forexample, from sunflower or colza plants obtained by genetic modificationor hybridization.

It is also possible to utilize used frying oils, various animal oils,such as fish oils, tallow, lard and even squaring greases.

Among the oils used it is also possible to indicate oils partiallymodified, for example, by polymerization or oligomerization, such as,for example, the stand oils of linseed oil and sunflower oil, and blownvegetable oils.

One particularly suitable glycerol may be obtained during the conversionof animal fats. Another particularly suitable glycerol may be obtainedduring the production of biodiesel. A third, very suitable glycerol maybe obtained during the conversion of animal or vegetable oils or fats bytransesterification in the presence of a heterogeneous catalyst, asdescribed in documents FR 2752242, FR 2869612 and FR 2869613. Morespecifically, the heterogeneous catalyst is selected from mixed oxidesof aluminum and zinc, mixed oxides of zinc and titanium, mixed oxides ofzinc, titanium and aluminum, and mixed oxides of bismuth and aluminum,and the heterogeneous catalyst is employed in the form of a fixed bed.This latter process may be a biodiesel production process.

The chloroethanol may be obtained starting from these raw materials byany process. The processes of hypochlorinating ethylene and ofchlorinating “synthetic” and/or “natural” ethylene glycol are preferred.The process of chlorinating “synthetic” and/or “natural” ethylene glycolis particularly preferred.

The chloropropanol may be obtained starting from these raw materials byany process. The processes of hypochlorinating propylene andchlorinating “synthetic” and/or “natural” propylene glycol arepreferred. The process of chlorinating “synthetic” and/or “natural”propylene glycol is particularly preferred.

The chloropropanediol may be obtained starting from these raw materialsby any process. The process of chlorinating “synthetic” and/or “natural”glycerol is preferred.

The dichloropropanol may be obtained starting from these raw materialsby any process. The processes of hypochlorinating allyl chloride,chlorinating allyl alcohol and chlorinating “synthetic” and/or “natural”glycerol are preferred. The process of chlorinating “synthetic” and/or“natural” glycerol is particularly preferred.

In the process for preparing the epoxide according to the invention, itis preferable for at least a fraction of the chlorohydrin to be preparedby chlorinating a polyhydroxylated aliphatic hydrocarbon. Thepolyhydroxylated aliphatic hydrocarbon may be “synthetic” or “natural”in the senses defined above.

In the preparation process according to the invention, when the epoxideis epichlorohydrin, preference is given to “natural” glycerol, in otherwords glycerol obtained in the course of biodiesel production or in thecourse of conversions of animal or vegetable oils or fats, theconversions being selected from saponification, transesterification andhydrolysis reactions. Glycerol obtained by transesterification of fatsor oils of vegetable or animal origin, the transesterification beingcarried out in the presence of a heterogeneous catalyst, is particularlypreferred. In the process for preparing the epoxide according to theinvention, the polyhydroxylated aliphatic hydrocarbon may be asdescribed in the patent application entitled “Process for preparingchlorohydrin by converting polyhydroxylated aliphatic hydrocarbons”,filed in the name of SOLVAY SA on the same day as the presentapplication, and the content of which is incorporated here by reference.

Particular mention is made of a process for preparing a chlorohydrinwherein a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof whose totalmetal content, the metals being expressed in the form of elements, isgreater than or equal to 0.1 μg/kg and less than or equal to 1000 mg/kg,is reacted with a chlorinating agent.

In the process for preparing the epoxide according to the invention, thechlorohydrin obtained starting from the polyhydroxylated aliphatichydrocarbon, from the ester of polyhydroxylated aliphatic hydrocarbon orfrom a mixture thereof by reaction with a chlorinating agent may beemployed, for example, in accordance with the process described inapplication WO 2005/054167 of SOLVAY SA, the content of which isincorporated here by reference.

In the process for preparing the epoxide according to the invention, thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon and the mixtures thereof may be a crude product ora purified product as described in application WO 2005/054167 of SOLVAYSA, from page 2 line 8 to page 4 line 2.

In the process for preparing the epoxide according to the invention, thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon and the mixture thereof may have an alkali metaland/or alkaline earth metal content of less than or equal to 5 g/kg, asdescribed in the application entitled “Process for preparing achlorohydrin by chlorinating a polyhydroxylated aliphatic hydrocarbon”,filed in the name of SOLVAY SA on the same day as the presentapplication, and the content of which is incorporated here by reference.

In the process according to the invention, the alkali metal and/oralkaline earth metal content of the polyhydroxylated aliphatichydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or amixture thereof is less than or equal to 5 g/kg, often less than orequal to 1 g/kg, more particularly less than or equal to 0.5 g/kg and,in certain cases, less than or equal to 0.01 g/kg. The alkali metaland/or alkaline earth metal content of the glycerol is generally greaterthan or equal to 0.1 μg/kg.

In the process according to the invention, the alkali metals aregenerally lithium, sodium, potassium and caesium, often sodium andpotassium, and frequently sodium.

In the process for preparing a chlorohydrin according to the invention,the lithium content of the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofis generally less than or equal to 1 g/kg, often less than or equal to0.1 g/kg and more particularly less than or equal to 2 mg/kg. Saidcontent is generally greater than or equal to 0.1 μg/kg.

In the process according to the invention, the sodium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the potassium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the rubidium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the caesium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the alkaline earth elementsare generally magnesium, calcium, strontium and barium, often magnesiumand calcium, and frequently calcium.

In the process according to the invention, the magnesium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the calcium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the strontium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the barium content of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof is generally less than orequal to 1 g/kg, often less than or equal to 0.1 g/kg and moreparticularly less than or equal to 2 mg/kg. Said content is generallygreater than or equal to 0.1 μg/kg.

In the process according to the invention, the alkali metals and/oralkaline earth metals are generally present in the form of salts,frequently in the form of chlorides, sulphates and mixtures thereof.Sodium chloride is the most often encountered.

In the process for preparing the epoxide according to the invention, thechlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of theester of polyhydroxylated aliphatic hydrocarbon or of the mixturethereof may be hydrogen chloride and/or hydrochloric acid as describedin application WO 2005/054167 of SOLVAY SA, from page 4 line 30 to page6 line 2.

Particular mention is made of a chlorinating agent which may be aqueoushydrochloric acid or hydrogen chloride which is preferably anhydrous.The hydrogen chloride may originate from a process for pyrolyzingorganic chlorine compounds, such as, for example, a vinyl chloridepreparation, a process for preparing 4,4-methylenediphenyl diisocyanate(MDI) or toluene diisocyanate (TDI), metal pickling processes, or thereaction of an inorganic acid such as sulphuric or phosphoric acid witha metal chloride such as sodium chloride, potassium chloride or calciumchloride.

In one advantageous embodiment of the process for preparing the epoxideaccording to the invention, the chlorinating agent of thepolyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylatedaliphatic hydrocarbon or of the mixture thereof is gaseous hydrogenchloride or an aqueous solution of hydrogen chloride or a combination ofthe two.

In the process for preparing the epoxide according to the invention, thechlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of theester of polyhydroxylated aliphatic hydrocarbon or of the mixturethereof may be aqueous hydrochloric acid or hydrogen chloride,preferably anhydrous, obtained from a process for preparing allylchloride and/or chloromethanes and/or of chlorinolysis and/or ofhigh-temperature oxidation of chlorine compounds, as described in theapplication entitled “Process for preparing a chlorohydrin by reacting apolyhydroxylated aliphatic hydrocarbon with a chlorinating agent”, filedin the name of SOLVAY SA on the same day as the present application, andthe content of which is incorporated here by reference.

Particular mention is made of a process for preparing a chlorohydrinfrom a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof and achlorinating agent, the latter agent containing at least one of thefollowing compounds: nitrogen, oxygen, hydrogen, chlorine, an organichydrocarbon compound, an organic halogen compound, an organic oxygencompound and a metal.

Particular mention is made of an organic hydrocarbon compound selectedfrom saturated or unsaturated aliphatic and aromatic hydrocarbons andmixtures thereof.

Particular mention is made of an unsaturated aliphatic hydrocarbonselected from acetylene, ethylene, propylene, butene, propadiene,methylacetylene and mixtures thereof, of a saturated aliphatichydrocarbon selected from methane, ethane, propane, butane and mixturesthereof, and of an aromatic hydrocarbon which is benzene.

Particular mention is made of an organic halogen compound which is anorganic chlorine compound selected from chloromethanes, chloroethanes,chloropropanes, chlorobutanes, vinyl chloride, vinylidene chloride,monochloropropenes, perchloroethylene, trichloroethylene,chlorobutadienes, chlorobenzenes and mixtures thereof.

Particular mention is made of an organic halogen compound which is anorganic fluorine compound selected from fluoromethanes, fluoroethanes,vinyl fluoride, vinylidene fluoride and mixtures thereof.

Particular mention is made of an organic oxygen compound selected fromalcohols, chloroalcohols, chloroethers and mixtures thereof.

Particular mention is made of a metal selected from alkali metals,alkaline earth metals, iron, nickel, copper, lead, arsenic, cobalt,titanium, cadmium, antimony, mercury, zinc, selenium, aluminum, bismuthand mixtures thereof.

Mention is made more particularly of a process wherein the chlorinatingagent is obtained at least partly from a process for preparing allylchloride and/or from a process for preparing chloromethanes and/or froma process of chlorinolysis and/or from a process of oxidizing chlorinecompounds at a temperature greater than or equal to 800° C.

In one advantageous embodiment of the process for preparing the epoxideaccording to the invention, the chlorinating agent of thepolyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylatedaliphatic hydrocarbon or of the mixture thereof contains no gaseoushydrogen chloride.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in a reactor as described in application WO2005/054167 of SOLVAY SA, at page 6 lines 3 to 23.

Mention is made particularly of plant made of or covered with materialswhich under the reaction conditions are resistant to chlorinatingagents, especially to hydrogen chloride. Mention is made moreparticularly of plant made of enameled steel or of tantalum.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in apparatus made of or covered with materials whichare resistant to chlorinating agents, as described in the applicationentitled “Process for preparing a chlorohydrin in corrosion-resistantapparatus”, filed in the name of SOLVAY SA on the same day as thepresent application, and the content of which is incorporated here byreference.

Particular mention is made of a process for preparing a chlorohydrinwhich comprises a step wherein a polyhydroxylated aliphatic hydrocarbon,an ester of a polyhydroxylated aliphatic hydrocarbon or a mixturethereof is subjected to reaction with a chlorinating agent containinghydrogen chloride and at least one other step carried out in apparatusmade of or covered with materials resistant to the chlorinating agentunder the conditions in which said step is performed. Mention is mademore particularly of metallic materials such as enameled steel, gold andtantalum and of non-metallic materials such as high-densitypolyethylene, polypropylene, poly(vinylidene fluoride),polytetrafluoroethylene, perfluoroalkoxyalkanes and poly(perfluoropropylvinyl ether), polysulphones and polysulphides, and graphite, includingimpregnated graphite.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in a reaction medium as described in the applicationentitled “Continuous process for preparing chlorohydrins”, filed in thename of SOLVAY SA on the same day as the present application, and thecontent of which is incorporated here by reference.

Particular mention is made of a continuous process for producingchlorohydrin wherein a polyhydroxylated aliphatic hydrocarbon, an esterof a polyhydroxylated aliphatic hydrocarbon or a mixture thereof isreacted with a chlorinating agent and an organic acid in a liquidreaction medium whose steady-state composition comprisespolyhydroxylated aliphatic hydrocarbon and esters of polyhydroxylatedaliphatic hydrocarbon with a sum content, expressed in moles ofpolyhydroxylated aliphatic hydrocarbon, of more than 1.1 mol % and lessthan or equal to 30 mol %, the percentage being based on the organicpart of the liquid reaction medium.

The organic part of the liquid reaction medium consists of all of theorganic compounds in the liquid reaction medium, in other words thecompounds whose molecule contains at least 1 carbon atom.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in the presence of a catalyst as described inapplication WO 2005/054167 of SOLVAY SA, from page 6 line 28 to page 8line 5.

Mention is made particularly of a catalyst based on a carboxylic acid oron a carboxylic acid derivative having an atmospheric boiling point ofgreater than or equal to 200° C., especially adipic acid and adipic acidderivatives.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out at a catalyst concentration, temperature and pressureand for residence times as described in application WO 2005/054167 ofSOLVAY SA, from page 8 line 6 to page 10 line 10.

Mention is made particularly of a temperature of at least 20° C. and notmore than 160° C., a pressure of at least 0.3 bar and not more than 100bar and a residence time of at least 1 h and not more than 50 h.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in the presence of a solvent as described inapplication WO 2005/054167 of SOLVAY SA, at page 11 lines 12 to 36.

Mention is made particularly of an organic solvent such as chlorinatedorganic solvent, an alcohol, a ketone, an ester or an ether, anon-aqueous solvent which is miscible with the polyhydroxylatedaliphatic hydrocarbon, such as chloroethanol, chloropropanol,chloropropanediol, dichloropropanol, dioxane, phenol, cresol, andmixtures of chloropropanediol and dichloropropanol, or heavy reactionproducts such as at least partly chlorinated and/or esterified oligomersof the polyhydroxylated aliphatic hydrocarbon.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofmay be carried out in the presence of a liquid phase comprising heavycompounds other than the polyhydroxylated aliphatic hydrocarbon, asdescribed in the application entitled “Process for preparing achlorohydrin in a liquid phase”, filed in the name of SOLVAY SA on thesame day as the present application, and the content of which isincorporated here by reference.

Particular mention is made of a process for preparing a chlorohydrinwherein a polyhydroxylated aliphatic hydrocarbon, an ester ofpolyhydroxylated aliphatic hydrocarbon or a mixture thereof is subjectedto reaction with a chlorinating agent in the presence of a liquid phasecomprising heavy compounds other than the polyhydroxylated aliphatichydrocarbon, the boiling temperature of said compounds under a pressureof 1 bar absolute being at least 15° C. greater than the boilingtemperature of the chlorohydrin under a pressure of 1 bar absolute.

In the process for preparing the epoxide according to the invention, thereaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon or the mixture thereofis preferably carried out in a liquid reaction medium. The liquidreaction medium may be single-phase or multi-phase.

The liquid reaction medium is composed of the entirety of the dissolvedor dispersed solid compounds, dissolved or dispersed liquid compoundsand dissolved or dispersed gaseous compounds at the reactiontemperature.

The reaction medium comprises the reactants, the catalyst, the solvent,the impurities present in the reactants, in the solvent and in thecatalyst, the reaction intermediates, the reaction products and thereaction by-products.

By reactants are meant the polyhydroxylated aliphatic hydrocarbon, theester of polyhydroxylated aliphatic hydrocarbon and the chlorinatingagent.

The impurities present in the polyhydroxylated aliphatic hydrocarbon mayinclude carboxylic acids, salts of carboxylic acids, fatty acid esterswith the polyhydroxylated aliphatic hydrocarbon, fatty acid esters withthe alcohols used in the transesterification, and inorganic salts suchas alkali metal or alkaline earth metal sulphates and chlorides.

When the polyhydroxylated aliphatic hydrocarbon is glycerol, theimpurities of the glycerol may include carboxylic acids, salts ofcarboxylic acids, fatty acid esters such as mono-, di- andtriglycerides, fatty acid esters with the alcohols used in thetransesterification, and inorganic salts such as alkali metal oralkaline earth metal sulphates and chlorides.

The reaction intermediates may include monochlorohydrins of thepolyhydroxylated aliphatic hydrocarbon and their esters and/orpolyesters, the esters and/or polyesters of the polyhydroxylatedaliphatic hydrocarbon, and the esters of polychlorohydrins.

When the chlorohydrin is dichloropropanol, the reaction intermediatesmay include the monochlorohydrin of glycerol and its esters and/orpolyesters, the esters and/or polyesters of glycerol, and the esters ofdichloropropanol.

The ester of polyhydroxylated aliphatic hydrocarbon may therefore be, asappropriate, a reactant, an impurity of the polyhydroxylated aliphatichydrocarbon or a reaction intermediate.

By reaction products are meant the chlorohydrin and water. The water maybe the water formed in the chlorination reaction and/or may be the waterintroduced into the process, for example via the polyhydroxylatedaliphatic hydrocarbon and/or the chlorinating agent, as described inapplication WO 2005/054167 of SOLVAY SA, at page 2 lines 22 to 28, atpage 3 lines 20 to 25, at page 5 lines 7 to 31 and at page 12 lines 14to 19.

The by-products may include, for example, partly chlorinated and/oresterified oligomers of the polyhydroxylated aliphatic hydrocarbon.

When the polyhydroxylated aliphatic hydrocarbon is glycerol, theby-products may include, for example, the partly chlorinated and/oresterified oligomers of glycerol.

The reaction intermediates and the by-products may be formed in thevarious steps of the process, such as, for example, during step (a) andduring the treatment steps subsequent to step (b).

The liquid reaction medium may thus comprise the polyhydroxylatedaliphatic hydrocarbon, the chlorinating agent, dissolved or dispersed inthe form of bubbles, the catalyst, the solvent, the impurities presentin the reactants, the solvent and the catalyst, such as dissolved orsolid salts, for example, the reaction intermediates, the reactionproducts and the reaction by-products.

Steps (a), (b) and (c) of the process for preparing the epoxideaccording to the invention may be conducted independently in batch modeor in continuous mode. Continuous mode is preferred. Continuous mode forthe 3 steps is particularly preferred.

In the preparation process according to the invention the organic acidmay be a product originating from the process for preparing thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedaliphatic hydrocarbon or the mixture thereof, or a product notoriginating from that process. In this latter case, the organic acid maybe an organic acid used to catalyze the reaction between thepolyhydroxylated aliphatic hydrocarbon and the chlorinating agent. Theorganic acid may also be a mixture of organic acid originating from theprocess for preparing the polyhydroxylated aliphatic hydrocarbon and anorganic acid not originating from the process for preparing thepolyhydroxylated aliphatic hydrocarbon. Preference is given to using anorganic acid which is not obtained during the preparation of thepolyhydroxylated aliphatic hydrocarbon, this acid being used as acatalyst of the reaction between the polyhydroxylated aliphatichydrocarbon and the chlorinating agent. Preference is given to using, inparticular, acetic acid or adipic acid.

In the process according to the invention, the esters of thepolyhydroxylated aliphatic hydrocarbon may originate from the reactionof the polyhydroxylated aliphatic hydrocarbon with an organic acid,before, during or within the steps which follow the reaction with thechlorinating agent.

In the process according to the invention, the chlorohydrin may beseparated from the other compounds of the reaction medium in accordancewith methods as described in application WO 2005/054167 of SOLVAY SA,from page 12 line 1 to page 16 line 35 and at page 18 lines 6 to 13.These other compounds are those mentioned above, and include unconsumedreactants, the impurities present in the reactants, the catalyst and thesolvent, the solvent, the catalyst, the reaction intermediates, thewater and the reaction by-products.

Particular mention is made of separation by azeotropic distillation of awater/chlorohydrin/chlorinating agent mixture under conditions whichminimize the losses of chlorinating agent, followed by separation of thechlorohydrin by decantation.

In the process for preparing the epoxide according to the invention, theseparation of the chlorohydrin and the other compounds from the reactionmedium from chlorination of the polyhydroxylated aliphatic hydrocarbon,the ester of polyhydroxylated aliphatic hydrocarbon or the mixturethereof may be carried out according to methods as described in patentapplication EP 05104321.4, filed in the name of SOLVAY SA on 20 May2005, and the content of which is incorporated here by reference. Aseparation method including at least one separating operation intendedto remove the salt from the liquid phase is particularly preferred.

Particular mention is made of a process for preparing a chlorohydrin byreacting a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof with achlorinating agent wherein the polyhydroxylated aliphatic hydrocarbon,an ester of a polyhydroxylated aliphatic hydrocarbon or a mixturethereof that is used contains at least one solid or dissolved metalsalt, the process including a separating operation intended to removepart of the metal salt. Mention is made more particularly of a processfor preparing a chlorohydrin by reacting a polyhydroxylated aliphatichydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon of amixture thereof with a chlorinating agent wherein the polyhydroxylatedaliphatic hydrocarbon, an ester of a polyhydroxylated aliphatichydrocarbon or a mixture thereof that is used contains at least onesodium and/or potassium chloride and/or sulphate and wherein theseparating operation intended to remove part of the metal salt is afiltering operation. Mention is also made particularly of a process forpreparing a chlorohydrin wherein (a) a polyhydroxylated aliphatichydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or amixture thereof is subjected to reaction with a chlorinating agent in areaction mixture, (b) a fraction of the reaction mixture containing atleast the water and the chlorohydrin is removed continuously orperiodically, (c) at least one part of the fraction obtained in step (b)is introduced into a distillation step, and (d) the reflux ratio of thedistillation step is controlled by supplying water to said distillationstep. Mention is made very particularly of a process for preparing achlorohydrin wherein (a) a polyhydroxylated aliphatic hydrocarbon, anester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereofis subjected to reaction with hydrogen chloride in a reaction mixture,(b) a fraction of the reaction mixture containing at least the water inthe chlorohydrin is removed continuously or periodically, (c) at leastpart of the fraction obtained in step (b) is introduced into adistillation step, wherein the ratio between the hydrogen chlorideconcentration and the water concentration in the fraction introducedinto the distillation step is smaller than the ratio of hydrogenchloride/water concentrations in the binary azeotropic hydrogenchloride/water composition at the distillation temperature and pressure.

In the process for preparing the epoxide according to the invention, thechlorohydrin and the other compounds can be separated from the reactionmedium from chlorination of the polyhydroxylated aliphatic hydrocarbon,the ester of polyhydroxylated aliphatic hydrocarbon or the mixturethereof by methods as described in the application entitled “Process forpreparing a chlorohydrin”, filed in the name of SOLVAY SA on the sameday as the present application, and the content of which is incorporatedhere by reference.

Particular mention is made of a process for preparing a chlorohydrincomprising the following steps: (a) a polyhydroxylated aliphatichydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or amixture thereof is reacted with a chlorinating agent and an organic acidso as to give a mixture containing the chlorohydrin and esters of achlorohydrin, (b) at least part of the mixture obtained in step (a) issubjected to one or more treatments in steps subsequent to step (a), and(c) polyhydroxylated aliphatic hydrocarbon is added to at least one ofthe steps subsequent to step (a), so as to react, at a temperaturegreater than or equal to 20° C., with the esters of the chlorohydrin, soas to form, at least partly, esters of the polyhydroxylated aliphatichydrocarbon. Mention is made more particularly of a process wherein thepolyhydroxylated aliphatic hydrocarbon is glycerol and the chlorohydrinis dichloropropanol.

In the process for preparing the epoxide according to the invention, thechlorohydrin and the other compounds can be separated from the reactionmedium from chlorination of the polyhydroxylated aliphatic hydrocarbon,the ester of polyhydroxylated aliphatic hydrocarbon or the mixturethereof by methods as described in the application entitled “Process forpreparing a chlorohydrin starting from a polyhydroxylated aliphatichydrocarbon”, filed in the name of SOLVAY SA on the same day as thepresent application, and the content of which is incorporated here byreference.

Particular mention is made of a process for preparing chlorohydrin byreacting a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof with achlorinating agent in a reactor which is supplied with one or moreliquid streams containing less than 50% by weight of thepolyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylatedhydrocarbon or the mixture thereof, relative to the weight of theentirety of the liquid streams introduced into the reactor. Moreparticular mention is made of a process comprising the following steps:(a) a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof is reactedwith a chlorinating agent so as to give at least one mixture containingthe chlorohydrin, water and the chlorinating agent, (b) at least afraction of the mixture formed in step (a) is removed, and (c) thefraction removed in step (b) is subjected to a distilling and/orstripping operation wherein polyhydroxylated aliphatic hydrocarbon isadded in order to separate, from the fraction removed in step (b), amixture containing water and the chlorohydrin, having a reducedchlorinating agent content as compared with that of the fraction removedin step (b).

In the process for preparing the epoxide according to the invention, thechlorohydrin and the other compounds of the reaction medium fromchlorination of the polyhydroxylated aliphatic hydrocarbon, the ester ofpolyhydroxylated aliphatic hydrocarbon or the mixture thereof may beseparated by methods as described in the application entitled “Processfor converting polyhydroxylated aliphatic hydrocarbons intochlorohydrins”, filed in the name of SOLVAY SA on the same day as thepresent application, and the content of which is incorporated here byreference.

Particular mention is made of a process for preparing a chlorohydrincomprising the following steps: (a) a polyhydroxylated aliphatichydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or amixture thereof is reacted with a chlorinating agent so as to give amixture containing the chlorohydrin, chlorohydrin esters and water, (b)at least a fraction of the mixture obtained in step (a) is subjected toa distilling and/or stripping treatment so as to give a batchconcentrated with water, with chlorohydrin and with chlorohydrin esters,and (c) at least a fraction of the batch obtained in step (b) issubjected to a separating operation in the presence of at least oneadditive so as to give a portion concentrated with chlorohydrin and withchlorohydrin esters and containing less than 40% by weight of water.

The separating operation is more particularly a decantation.

In the process for preparing the epoxide according to the invention, theseparation and the treatment of the other compounds of the reactionmedium from chlorination of the polyhydroxylated aliphatic hydrocarbon,the ester of polyhydroxylated aliphatic hydrocarbon or the mixturethereof may be carried out by methods as described in the applicationentitled “Process for preparing a chlorohydrin by chlorinating apolyhydroxylated aliphatic hydrocarbon”, filed in the name of SOLVAY SAon the same day as the present application. One preferred treatmentconsists in subjecting a fraction of the reaction by-products to ahigh-temperature oxidation.

Particular mention is made of a process for preparing a chlorohydrincomprising the following steps: (a) a polyhydroxylated aliphatichydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or amixture thereof whose alkali metal and/or alkaline earth metal contentis less than or equal to 5 g/kg, a chlorinating agent and an organicacid are reacted so as to give a mixture containing at least thechlorohydrin and by-products, (b) at least part of the mixture obtainedin step (a) is subjected to one or more treatments in steps subsequentto step (a), and (c) at least one of the steps subsequent to step (a)consists in an oxidation at a temperature greater than or equal to 800°C. More particular mention is made of a process wherein, in thesubsequent step, a part of the mixture obtained in step (a) is removedand this part is subjected to oxidation at a temperature greater than orequal to 800° C. in the course of its removal. Particular mention isalso made of a process wherein the treatment of step (b) is a separatingoperation selected from decantation, filtration, centrifugation,extraction, washing, evaporation, stripping, distillation and adsorptionoperations or combinations of at least two thereof.

In the process according to the invention, when the chorohydrin ischloropropanol, said chloropropanol is generally obtained in the form ofa mixture of compounds comprising the isomers of 1-chloropropan-2-ol andof 2-chloropropan-1-ol. This mixture generally contains more than 1% byweight of the two isomers, preferably more than 5% by weight and inparticular more than 50%. The mixture usually contains less than 99.9%by weight of the two isomers, preferably less than 95% by weight andvery particularly less than 90% by weight. The other constituents of themixture may be compounds originating from the processes for preparingthe chloropropanol, such as residual reactants, reaction by-products,solvents and, in particular, water.

The mass ratio between the isomers 1-chloropropan-2-ol and2-chloropropan-1-ol is usually greater than or equal to 0.01, preferablygreater than or equal to 0.4. This ratio is usually less than or equalto 99 and preferably less than or equal to 25.

In the process according to the invention, when the chorohydrin ischloroethanol, said chloroethanol is generally obtained in the form of amixture of compounds comprising the isomer 2-chloroethanol. This mixturegenerally contains more than 1% by weight of the isomer, preferably morethan 5% by weight and in particular more than 50%. The mixture usuallycontains less than 99.9% by weight of the isomer, preferably less than95% by weight and very particularly less than 90% by weight. The otherconstituents of the mixture may be compounds originating from theprocesses for preparing the chloroethanol, such as residual reactants,reaction by-products, solvents and, in particular, water.

In the process according to the invention, when the chlorohydrin isdichloropropanol, said dichloropropanol is generally obtained in theform of a mixture of compounds comprising the isomers of1,3-dichloropropan-2-ol and of 2,3-dichloropropan-1-ol. This mixturegenerally contains more than 1% by weight of the two isomers, preferablymore than 5% by weight and in particular more than 50%. The mixtureusually contains less than 99.9% by weight of the two isomers,preferably less than 95% by weight and very particularly less than 90%by weight. The other constituents of the mixture may be compoundsoriginating from the processes for preparing the dichloropropanol, suchas residual reactants, reaction by-products, solvents and, inparticular, water.

The mass ratio between the isomers 1,3-dichloropropan-2-ol and2,3-dichloropropan-1-ol is usually greater than or equal to 0.01, oftengreater than or equal to 0.4, frequently greater than or equal to 1.5,preferably greater than or equal to 3.0, more preferably greater than orequal to 7.0 and, with very particular preference, greater than or equalto 20.0. This ratio is usually less than or equal to 99 and preferablyless than or equal to 25.

In the process according to the invention, when the chlorohydrin isdichloropropanol and is obtained in a process starting from allylchloride, the isomer mixture exhibits a1,3-dichloropropan-2-ol:2,3-dichloropropan-1-ol mass ratio which isoften from 0.3 to 0.6, typically approximately 0.5. When thedichloropropanol is obtained in a process starting from synthetic and/ornatural glycerol, the 1,3-dichloropropan-2-ol:2,3-dichloropropan-1-olmass ratio is commonly greater than or equal to 1.5, preferably greaterthan or equal to 3.0 and very particularly greater than or equal to 9.0.When the dichloropropanol is obtained starting from allyl alcohol, the1,3-dichloropropan-2-ol:2,3-dichloropropan-1-ol mass ratio is often ofthe order of 0.1.

In the process according to the invention, when the chlorohydrin isdichloropropanol, the mixture of isomers exhibits a1,3-dichloropropan-2-ol: 2,3-dichloropropan-1-ol mass ratio of generallygreater than or equal to 0.5, often greater than or equal to 3 andfrequently greater than or equal to 20.

In the process for preparing the epoxide according to the invention, thechlorohydrin may include a high halogenated ketone content, particularlyof chloroacetone, as described in patent application FR 05.05120 of May20, 2005, filed in the name of the applicant, and the content of whichis incorporated here by reference. The halogenated ketone content may bereduced by subjecting the chlorohydrin obtained in the process accordingto the invention to an azeotropic distillation in the presence of water,or by subjecting the chlorohydrin to a dehydrochlorination treatment asdescribed in this application, from page 4 line 1 to page 6 line 35.

Particular mention is made of a process for preparing an epoxide whereinhalogenated ketones are formed as by-products, and which comprises atleast one treatment for removing at least some of the halogenatedketones formed. Mention is made more particularly of a process forpreparing an epoxide by dehydrochlorinating a chlorohydrin at least afraction of which is prepared by chlorinating a polyhydroxylatedaliphatic hydrocarbon, an ester of a polyhydroxylated aliphatichydrocarbon or a mixture thereof, a dehydrochlorination treatment, and atreatment by azeotropic distillation of a water/halogenated ketonemixture, the intention of which is to remove at least some of thehalogenated ketones formed, and a process for preparing epichlorohydrinwherein the halogenated ketone formed is chloroacetone.

In the process for preparing an epoxide according to the invention, thechlorohydrin may be subjected to a dehydrochlorination reaction toproduce an epoxide as described in patent applications WO 2005/054167and FR 05.05120, both filed in the name of SOLVAY SA.

In the process for preparing an epoxide according to the invention, theepoxide is formed during the reaction of dehydrochlorinating thechlorohydrin with the basic compound.

In a first embodiment of the process for preparing an epoxide accordingto the invention, a fraction of the reaction medium obtained in step (a)is withdrawn, this fraction having the same composition as the reactionmedium obtained in step (a), and the basic compound is added to itduring the withdrawal.

The chlorohydrin content of this fraction is generally greater than orequal to 10 g/kg, often greater than or equal to 400 g/kg and inparticular greater than or equal to 500 g/kg. Said content is generallyless than or equal to 750 g/kg, often less than or equal to 650 g/kg andin particular less than or equal to 600 g/kg.

The chlorinating agent content of the fraction of the mixture obtainedin step (a) is generally greater than or equal to 10 g/kg, often greaterthan or equal to 20 g/kg and in particular greater than or equal to 30g/kg. Said content is generally less than or equal to 150 g/kg, oftenless than or equal to 130 g/kg and in particular less than or equal to100 g/kg.

The total organic acid content of the fraction of the mixture obtainedin step (a) is generally greater than or equal to 1 g/kg, often greaterthan or equal to 2 g/kg and in particular greater than or equal to 5g/kg. Said content is generally less than or equal to 40 g/kg, oftenless than or equal to 20 g/kg and in particular less than or equal to 10g/kg. By total organic acid content is meant the sum of the amounts oforganic acid per se, of esters of the organic acid and of salts of theorganic acid, this sum being expressed as organic acid per se.

In a second embodiment of the process for preparing an epoxide accordingto the invention, a fraction of the medium obtained in step (a) iswithdrawn, this fraction having the same composition as the reactionmedium obtained in step (a), this fraction is subjected to one or moreseparation treatments, for example evaporation, stripping and/ordistillation, so as to give a part enriched with chlorohydrin and withwater.

The concentrations of the different species present in this part mayvary greatly as a function in particular of the raw materials employed,for example the type of chlorinating agent, hydrogen chloride inanhydrous form or in aqueous solution, the water content of thepolyhydroxylated aliphatic hydrocarbon or else the type of organic acidused as catalyst, or as a function of the separation treatment.Surprisingly the process according to the present invention may beemployed in all of these cases.

The chlorohydrin content of the part enriched with chlorohydrin and withwater is generally greater than or equal to 10 g/kg, often greater thanor equal to 400 g/kg and in particular greater than or equal to 500g/kg. Said content is generally less than or equal to 750 g/kg, oftenless than or equal to 600 g/kg and in particular less than or equal to700 g/kg.

The chlorinating agent content of this part is generally greater than orequal to 10 g/kg, often greater than or equal to 20 g/kg and inparticular greater than or equal to 30 g/kg. Said content is generallyless than or equal to 150 g/kg, often less than or equal to 130 g/kg andin particular less than or equal to 100 g/kg.

The total organic acid content of this part is generally greater than orequal to 1 g/kg, often greater than or equal to 2 g/kg and in particulargreater than or equal to 5 g/kg. Said content is generally less than orequal to 40 g/kg, often less than or equal to 25 g/kg and in particularless than or equal to 100 g/kg.

In a first variant of this second embodiment, the basic compound isadded to this part enriched with chlorohydrin and with water.

In a second variant of this second embodiment, the part enriched withchlorohydrin and with water is subjected to a decantation so as to givea first portion enriched with water and a second portion enriched withchlorohydrin.

This decantation may be carried out, for example, in the refluxreservoir of a distillation column or at any desired subsequent stage,such as, for example, a stage of storage or of secondary distillationfor the purposes of purification. The devices for carrying out thisphase separation are described for example in Perry's ChemicalEngineers' Handbook, Sixth Edition, Robert H. Perry, Don Green, 1984,sections 21-64 to 21-68.

The chlorohydrin, water and chlorinating agent contents in these twoportions may be easily deduced from the ternary diagrams of thecompositions of chlorohydrin/water/chlorinating agent mixtures. Aternary diagram of this kind for the 1,3-dichloropropanol/water/hydrogenchloride mixture may be found in G. P. Gibson, The preparation,properties, and uses of glycerol derivatives, Part III, Thechlorohydrins, pages 970 to 975.

The first portion may contain the chlorohydrin. The chlorohydrin contentis generally less than or equal to 300 g/kg, often less than or equal to250 g/kg and in particular less than or equal to 200 g/kg.

The chlorinating agent content of this first portion is generallygreater than or equal to 1 g/kg, often greater than or equal to 10 g/kgand in particular greater than or equal to 20 g/kg. Said content isgenerally less than or equal to 250 g/kg, often less than or equal to200 g/kg and in particular less than or equal to 150 g/kg.

The total organic acid content of this first portion is generallygreater than or equal to 1 g/kg, often greater than or equal to 2 g/kgand in particular greater than or equal to 3 g/kg. Said content isgenerally less than or equal to 100 g/kg, often less than or equal to 50g/kg and in particular less than or equal to 30 g/kg.

The chlorohydrin content of the second portion is generally greater thanor equal to 600 g/kg, often greater than or equal to 700 g/kg and inparticular greater than or equal to 800 g/kg.

The chlorinating agent content of this second portion is generallygreater than or equal to 1 g/kg, often greater than or equal to 5 g/kgand in particular greater than or equal to 10 g/kg. Said content isgenerally less than or equal to 50 g/kg, often less than or equal to 40g/kg and in particular less than or equal to 30 g/kg.

The organic acid content of this second portion is generally greaterthan or equal to 1 g/kg, often greater than or equal to 5 g/kg and inparticular greater than or equal to 10 g/kg. Said content is generallyless than or equal to 150 g/kg, often less than or equal to 70 g/kg andin particular less than or equal to 30 g/kg.

The chlorohydrin ester content of this second portion is generallygreater than or equal to 1 g/kg, often greater than or equal to 5 g/kgand in particular greater than or equal to 10 g/kg. Said content isgenerally less than or equal to 140 g/kg, often less than or equal to 70g/kg and in particular less than or equal to 30 g/kg.

In a first aspect of this second variant, the basic agent is addedsolely to the first portion enriched with water.

In a second aspect of this second variant, the basic agent is addedsolely to the second portion enriched with chlorohydrin.

In a third aspect of this second variant, the basic agent is added tothe first portion enriched with water and to the second portion enrichedwith chlorohydrin.

In a fourth aspect of this second variant, the basic agent is added to amixture of the first portion enriched with water and the second portionenriched with chlorohydrin. The mixture may contain variable proportionsof these two portions. The ratio by weight of the first portion enrichedwith water to the second portion enriched with chlorohydrin variesgenerally from 1/99 to 99/1, often from 89/11 to 11/89, frequently from81/19 to 19/81, and in particular from 41/59 to 59/41.

An advantage of this second variant is that it is possible to knowexactly the composition of the portions deployed in thedehydrochlorination reaction with the basic agent. This is because thecomposition of each of the portions is defined by the conditions underwhich the phase separation is operated, such as the temperature, thepressure and the composition of the fraction of the mixture obtained instep (a), including in particular the chlorinating agent content, theorganic acid content and the chlorohydrin ester content. Knowledge ofthe composition of each of the portions deployed in thedehydrochlorination reaction in step (c) makes it possible to controlthis step more effectively.

In a third embodiment of the process for preparing an epoxide accordingto the invention, a fraction of the medium obtained in step (a) iswithdrawn, this fraction having the same composition as the reactionmedium obtained in step (a), this fraction is subjected to anevaporating, stripping or distillation treatment so as to give a partenriched with chlorohydrin, and the basic compound is added to thispart.

The chlorohydrin content of this part is generally greater than or equalto 100 g/kg, often greater than or equal to 200 g/kg and in particulargreater than or equal to 400 g/kg.

The chlorinating agent content of this part is generally greater than orequal to 0.01 g/kg, often greater than or equal to 0.05 g/kg and inparticular greater than or equal to 0.1 g/kg. Said content is generallyless than or equal to 110 g/kg, often less than or equal to 80 g/kg andin particular less than or equal to 65 g/kg.

The organic acid content of this part is generally greater than or equalto 0.01 g/kg, often greater than or equal to 0.1 g/kg and in particulargreater than or equal to 1 g/kg. Said content is generally less than orequal to 270 g/kg, often less than or equal to 200 g/kg and inparticular less than or equal to 130 g/kg.

Evaporation is intended to denote the separation of a substance byheating, under reduced pressure where appropriate.

Stripping is intended to denote the separation of a substance byvapour-mediated entrainment from a body which does not dissolve in saidsubstance. In the process according to the invention, this body may beany desired compound which is inert relative to the chlorohydrin, suchas, for example, water vapour, air, nitrogen or carbon dioxide. Thesesame compounds may constitute the gaseous stream optionally present inthe evaporation treatment.

Distillation is intended to denote the direct passage from the liquidstate to the gaseous state and then condensation of the vapoursobtained. By fractional distillation is meant a sequence ofdistillations conducted on the vapours successively condensed. Thefractional distillation treatment is preferred.

The various embodiments may be combined with one another in any desiredway.

By basic compound is meant basic organic compounds or basic inorganiccompounds. Basic inorganic compounds are preferred. These basicinorganic compounds may be oxides, hydroxides and salts of metals, suchas carbonates, hydrogen carbonates, phosphates or mixtures thereof, forexample. Among the metals, preference is given to alkali metals andalkaline earth metals. Sodium, potassium and calcium and mixturesthereof are particularly preferred. The basic inorganic compounds may bepresent in the form of solids, liquids or aqueous or organic solutionsor suspensions. Aqueous solutions or suspensions are preferred. Thesolutions and suspensions of NaOH, of Ca(OH)₂, purified alkaline brineand mixtures thereof are particularly preferred. By purified alkalinebrine is meant the caustic soda, containing NaCl, of the kind producedin a diaphragm electrolysis process. The amount of basic compound in thesolution or suspension is generally greater than or equal to 1% byweight and preferably greater than or equal to 4% by weight. This amountis commonly less than or equal to 60% by weight. An amount ofapproximately 50% by weight is particularly appropriate.

The basic compound may be used in superstoichiometric, substoichiometricor stoichiometric amounts with respect to the chlorohydrin. When thebasic compound is used in substoichiometric amounts it is usual to usenot more than 2 moles of chlorohydrin per mole of base. It is common touse not more than 1.5 moles of chlorohydrin per mole of base andpreferably not more than 1.05 moles of chlorohydrin per mole of base.When the basic agent is used in superstoichiometric amounts use is madeof not more than 2 moles of base per mole of chlorohydrin. In this caseit is customary to use at least 1.05 moles of base per mole ofchlorohydrin.

The process for preparing the epoxide according to the invention may beintegrated into an overall scheme for preparing an epoxide as describedin the application entitled “Process for preparing an epoxide from achlorohydrin”, filed in the name of SOLVAY SA on the same day as thepresent application, and the content of which is incorporated here byreference.

Particular mention is made of a process for preparing an epoxide thatcomprises at least one step of purifying the epoxide formed, the epoxidebeing at least partly prepared by a process for dehydrochlorinating achlorohydrin, the latter being at least partly prepared by a process forchlorinating a polyhydroxylated aliphatic hydrocarbon, an ester of apolyhydroxylated aliphatic hydrocarbon or a mixture thereof.

In the process according to the invention, the polyhydroxylatedaliphatic hydrocarbon is preferably glycerol, the chlorohydrin ispreferably dichloropropanol and the epoxide is preferablyepichlorohydrin.

When the epoxide is epichlorohydrin the epoxide may be used forproducing epoxy resins.

FIG. 1 shows one particular scheme of plant which can be used forimplementing the separation process according to the invention.

A reactor (4) is supplied in continuous mode or in batch mode with thepolyhydroxylated aliphatic hydrocarbon, the ester of thepolyhydroxylated aliphatic hydrocarbon or the mixture thereof via line(1) and with catalyst via line (2); the chlorinating agent is suppliedin continuous mode or in batch mode via line (3); a distillation column(6) is supplied via line (5) with vapours produced in reactor (4); astream is withdrawn from column (6) via line (7) and is introduced intoa condenser (8), the stream obtained from the condenser is introducedvia line (9) into a phase separator (10), in which the aqueous phase andorganic phase are separated. A fraction of the stream from line (7) maybe withdrawn and conveyed into dehydrochlorinating reactor (31) via line(37). Dehydrochlorinating reactor (31) is supplied with basic agent vialine (32). A stream containing the epoxide is withdrawn from reactor(31) via line (40). A fraction of the aqueous phase separated in phaseseparator (10) is optionally recycled via line (11) to the top of thecolumn in order to maintain the reflux. Fresh water may be introducedinto line (11) via line (12). The production of chlorohydrin isdistributed between the organic phase withdrawn via line (14) and theaqueous phase withdrawn via line (13). A fraction of the stream fromline (13) may be withdrawn and conveyed into a dehydrochlorinatingreactor (31) via line (38). A fraction of the stream from line (14) maybe withdrawn and conveyed into a dehydrochlorinating reactor (31) vialine (39). Another part of the stream from line (14) may optionally beconveyed to the reflux of column (6) via line (30). The residue fromcolumn (6) may be recycled to reactor (4) via line (15). A fraction ofheavy products is withdrawn from the reactor and is introduced via line(17) into an evaporator (18), in which a partial evaporation isconducted, for example, by heating or by gas purging with nitrogen orwater vapour; the gaseous phase containing the majority of thechlorinating agent from stream (17) is recycled via line (19) to column(6) or via line (20) to reactor (4). Another fraction of heavy productsis withdrawn from reactor (4) via line (16), a part of which is conveyedinto a dehydrochlorinating reactor (31) via line (34). A fraction of thestream from line (17) may be withdrawn and conveyed into adehydrochlorinating reactor (31) via line (35). A fraction of the streamfrom line (21) may be withdrawn and conveyed into a dehydrochlorinatingcolumn (31) via line (33). A distillation or stripping column (22) issupplied with the liquid phase from stripping apparatus (18) via line(21); the major part of the chlorohydrin is collected at the top ofcolumn (22) via line (23) and the residue, which contains esters of thepolyhydroxylated aliphatic hydrocarbon and the chlorohydrin isintroduced via line (24) into the filtration column (25), in which theliquid phase and solid phase are separated; the liquid phase is recycledvia line (26) to reactor (4). A fraction of the stream from line (23)may be withdrawn and conveyed into a dehydrochlorinating column (31) vialine (36). A solid may be withdrawn from the filtration unit (25) vialine (27) in the form of a solid or of a solution. Solvents may be addedto filtration unit (25) via lines (28) and (29) for the washing and/orthe dissolving of the solid, and may be withdrawn via line (27).

The examples which follow are intended to illustrate the invention,though without subjecting it to any limitation.

EXAMPLE 1 In Accordance with the Invention

A mixture containing 80 g of dichloropropanol (0.62 mol), 9.7 g ofhydrogen chloride (0.27 mol), 30 g of water and 1.3 g of acetic acid ispreheated to 95° C. in a reactor surmounted by a distillation column.Over 30 minutes 132 g of a 280 g/kg aqueous solution of caustic soda areadded thereto at a temperature of 95° C. and at a pressure of 0.59 bar.A mixture containing epichlorohydrin and water is removed continuously.After 20 minutes of additional reaction, after the end of the addition,53.9 g of epichlorohydrin (0.58 mol) are recovered.

EXAMPLE 2 In Accordance with the Invention

A mixture containing 80 g of dichloropropanol (0.62 mol), 9.7 g ofhydrogen chloride (0.27 mol), 900 g of water and 1.3 g of acetic acid ispreheated to 95° C. in a reactor surmounted by a distillation column.Over 30 minutes 132 g of a 280 g/kg aqueous solution of caustic soda areadded thereto at a temperature of 95° C. and at a pressure of 0.59 bar.A mixture containing epichlorohydrin and water is removed continuously.After 40 minutes of additional reaction, after the end of the addition,52.2 g of epichlorohydrin (0.56 mol) are recovered.

1. A process for preparing an epoxide, wherein a reaction mediumresulting from the reaction of a polyhydroxylated aliphatic hydrocarbon,an ester of a polyhydroxylated aliphatic hydrocarbon or a mixturethereof with a chlorinating agent, the reaction medium containing atleast 10 g of chlorohydrin per kg of reaction medium, is subjected to asubsequent chemical reaction without intermediate treatment.
 2. Theprocess according to claim 1, wherein the subsequent chemical reactionis a dehydrochlorination reaction.
 3. The process according to claim 2,wherein the dehydrochlorination reaction is carried out by adding abasic compound to the reaction medium.
 4. A process for preparing anepoxide, comprising: (a) a polyhydroxylated aliphatic hydrocarbon, anester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereofis reacted with a chlorinating agent and an organic acid so as to formthe chlorohydrin and chlorohydrin esters in a reaction medium containingthe polyhydroxylated aliphatic hydrocarbon, the ester of apolyhydroxylated aliphatic hydrocarbon, water, the chlorinating agentand the organic acid, the reaction medium containing at least 10 g ofchlorohydrin per kg of reaction medium (b) at least a fraction of thereaction medium obtained in step (a), this fraction having the samecomposition as the reaction medium obtained in step (a), is subjected toone or more treatments in steps subsequent to step (a), and (c) a basiccompound is added to at least one of the steps subsequent to step (a),in order to react at least partially with the chlorohydrin, thechlorohydrin esters, the chlorinating agent and the organic acid, so asto form the epoxide and salts.
 5. The process according to claim 4,wherein, in the subsequent step, a fraction of the reaction mediumobtained in step (a) is withdrawn, this fraction having the samecomposition as the reaction medium obtained in step (a), and the basiccompound is added to it during the withdrawal.
 6. The process accordingto claim 4, wherein, in the subsequent step, a fraction of the reactionmedium obtained in step (a) is withdrawn, this fraction having the samecomposition as the reaction medium obtained in step (a), this fractionis subjected to a treatment of evaporating and/or stripping and/ordistilling so as to give a part enriched with chlorohydrin, withchlorohydrin esters and with water, and the basic compound is added tothe part enriched with chlorohydrin, with chlorohydrin esters and withwater.
 7. The process according to claim 6, wherein the part enrichedwith chlorohydrin, with chlorohydrin ester and with water is subjectedto a decantation treatment so as to give a first position enriched withwater and a second portion enriched with chlorohydrin and withchlorohydrin ester, and the basic agent is added to the first portion,to the second portion or to a mixture of the two portions.
 8. Theprocess according to claim 7, wherein the mass ratio between the firstportion and the second portion in the mixture is greater than or equalto 1/99 and less than or equal to 99/1.
 9. The process according toclaim 4, wherein, in the subsequent step, a fraction of the reactionmedium obtained in step (a) is withdrawn, this fraction having the samecomposition as the reaction medium obtained in step (a), this fractionis subjected to a distillation treatment so as to give a part enrichedwith chlorohydrin and with chlorohydrin ester, and the basic compound isadded to this part.
 10. The process according to claim 4, wherein thefraction of the reaction medium obtained in step (a) has a chlorohydrincontent of greater than or equal to 100 g/kg and less than or equal to700 g/kg, a chlorinating agent content of greater than 1 g/kg and lessthan or equal to 200 g/kg and a total organic acid content of greaterthan or equal to 1 g/kg and less than or equal to 500 g/kg.
 11. Theprocess according to claim 6, wherein the part enriched withchlorohydrin and with water has a chlorohydrin content of greater thanor equal to 10 g/kg and less than or equal to 850 g/kg, a chlorinatingagent content of greater than 0.01 g/kg and less than or equal to 110g/kg of chlorinating agent and a total organic acid content of greaterthan or equal to 0.01 g/kg and less than or equal to 270 g/kg of organicacid.
 12. The process according to claim 7, wherein the portion enrichedwith water has a chlorohydrin content of less than or equal to 500 g/kgof chlorohydrin, a chlorinating agent content of greater than 5 g/kg andless than or equal to 500 g/kg and a total organic acid content ofgreater than or equal to 0.01 g/kg and less than or equal to 5 mol/kg,and the portion enriched with chlorohydrin contains at least 400 g/kg ofchlorohydrin, from 1 ppm by weight to 50 g/kg of chlorinating agent andfrom 0.0001 to 5 mol/kg of organic acid.
 13. The process according toclaim 9, wherein the part enriched with chlorohydrin has a chlorohydrincontent of greater than or equal to 100 g/kg, a chlorinating agentcontent of greater than 0.01 g/kg and less than or equal to 110 g/kg anda total organic acid content of greater than or equal to 0.01 g/kg andless than or equal to 270 g/kg.
 14. The process according to claim 1,wherein the polyhydroxylated aliphatic hydrocarbon, the ester of apolyhydroxylated aliphatic hydrocarbon or the mixture thereof isobtained starting from renewable materials.
 15. The process according toclaim 1, wherein the chlorinating agent contains hydrogen chloride. 16.The process according to claim 15, wherein the hydrogen chloride is acombination of gaseous hydrogen chloride and an aqueous solution ofhydrogen chloride, or is an aqueous solution of hydrogen chloride. 17.The process according to claim 4, wherein the reaction of step (a) iscatalyzed by the organic acid and the organic acid is not obtainedduring a process for preparing the polyhydroxylated aliphatichydrocarbon.
 18. The process according to claim 4, wherein the organicacid is acetic acid or adipic acid.
 19. The process according to claim3, wherein the basic compound is selected from aqueous solutions orsuspensions of NaOH, of Ca(OH)₂, purified alkaline brine and mixturesthereof and wherein the molar ratio of the basic compound and thechlorohydrin is greater than or equal to 0.5 and less than or equal to2.
 20. The process according to claim 1, wherein the polyhydroxylatedaliphatic hydrocarbon is selected from ethylene glycol, propyleneglycol, chloropropanediol, glycerol and mixtures of at least twothereof.
 21. The process according to claim 1, wherein the chlorohydrinis selected from chloroethanol, chloropropanol, chloropropanediol,dichloropropanol and mixtures of at least two thereof.
 22. The processaccording to claim 1, wherein the epoxide is selected from ethyleneoxide, propylene oxide, glycidol, epichlorohydrin and mixtures of atleast two thereof.
 23. The process according to claim 1, wherein thepolyhydroxylated aliphatic hydrocarbon is glycerol, the chlorohydrin isdichloropropanol and the epoxide is epichlorohydrin.
 24. The processaccording to claim 23, wherein the epichlorohydrin is used for producingepoxy resins.
 25. A process for preparing epichlorohydrin, wherein amixture containing dichloropropanol, hydrogen chloride and an organicacid is reacted with an aqueous solution of a basic agent.